The deadly fighting came after Sergio Cabral, Rio's state governor, asked Luiz Inacio Lula da Silva, the president of Brazil, at the beginning of the month to send military troops to help curb the soaring crime in the city.

In Brazil, local police are usually expected to ensure the security of each individual state.

Lula promised to send in the troops, but prolonged negotiations with the armed forces had postponed the move.

Rio Body Count, a website that uses media reports to tally the number of dead and injured in violence in the city, said 710 people had died there since the beginning of February.

The city's security secretariat meanwhile put the number of dead since the beginning of the year at around a thousand.